Solved

How to scroll to middle of page (with jquery)

Posted on 2014-04-29
4
2,526 Views
Last Modified: 2014-04-29
Hello experts
I 'm using a function to add a new div onclick loading the content with an ajax call.
The problem is that i cant scroll the new div to the middle of the page.
Below my code.
Any help to fix this?
// JavaScript Document
 $('#adddiv').live('click', function () {
   $.ajax({
     type: "POST",
     url: "thisfunction.cfc?returnformat=json",
     data: {
       method: 'fgetinstruction'
     },
     success: function (f) {
       var formattedResponse = $.parseJSON(f);
       if (jQuery.isArray(formattedResponse) === true) {
         var success = formattedResponse[0]['success'];
         var content = formattedResponse[0]['content'];
         var newid = formattedResponse[0]['newid'];
         if (success === true) {
           $(content).appendTo(instruc);
           $('#' + newid).scrolltocenter();
           return false;
         }
       }
     }
   }, "json")
 });
 jQuery.fn.scrolltocenter = function () {
   var scrollto = this.offset().top + (this.height() / 2);
   this.animate({
     scrollTop: scrollto
   });
   return this;
 }

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Question by:Panos
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4 Comments
 
LVL 56

Accepted Solution

by:
Julian Hansen earned 500 total points
ID: 40029220
Firstup consider changing .live() to .on() - the former is being deprecated.

Secondly - set your dataType : 'json' - that way you won't have to use this line

var formattedResponse = $.parseJSON(f);

As you have it at the moment is the method used for .post() i.e. to add the 'json' parameter after the definition of the callback.

For .ajax use
type: "POST",
     url: "thisfunction.cfc?returnformat=json",
     data: {
       method: 'fgetinstruction'
     },
     dataType: 'json',
     success: 
...
}

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Then to your actual problem
1. You need to subtract from offset top not add
2. The value you need to subtract is half the difference between the window height and the height of your div
3. Finally - you need to scroll the body not the div
Here is some code that should do what you want
 jQuery.fn.scrolltocenter = function () {
   var scrollto = this.offset().top - (($(window).height() - this.height())/ 2);
   $('html,body').animate({
     scrollTop: scrollto
   });
   return this;
 }

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0
 
LVL 2

Author Comment

by:Panos
ID: 40029234
Hi  julianH
Thank you for your correction and the great help.
It is working fine
0
 
LVL 2

Author Closing Comment

by:Panos
ID: 40029235
Thank you
regards
panos
0
 
LVL 56

Expert Comment

by:Julian Hansen
ID: 40029398
You are welcome - thanks for the points.
0

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